Commit 1d58f5ef authored by Chris Packham's avatar Chris Packham Committed by Guenter Roeck
Browse files

hwmon: (adt7475) fan stall prevention 



By default adt7475 will stop the fans (pwm duty cycle 0%) when the
temperature drops past Tmin - hysteresis. Some systems want to keep the
fans moving even when the temperature drops so add new sysfs attributes
that configure the enhanced acoustics min 1-3 which allows the fans to
run at the minimum configure pwm duty cycle.

Signed-off-by: default avatarChris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent e4651640

Documentation/hwmon/adt7475

+5 −0
Original line number Diff line number Diff line
@@ -109,6 +109,11 @@ fan speed) is applied. PWM values range from 0 (off) to 255 (full speed). 
Fan speed may be set to maximum when the temperature sensor associated with

the PWM control exceeds temp#_max.



At Tmin - hysteresis the PWM output can either be off (0% duty cycle) or at the

minimum (i.e. auto_point1_pwm). This behaviour can be configured using the

pwm[1-*]_stall_disable sysfs attribute. A value of 0 means the fans will shut

off. A value of 1 means the fans will run at auto_point1_pwm.



Notes

-----

drivers/hwmon/adt7475.c

+50 −0
Original line number Diff line number Diff line
@@ -79,6 +79,9 @@ 


#define REG_TEMP_TRANGE_BASE	0x5F



#define REG_ENHANCE_ACOUSTICS1	0x62

#define REG_ENHANCE_ACOUSTICS2	0x63



#define REG_PWM_MIN_BASE	0x64



#define REG_TEMP_TMIN_BASE	0x67
@@ -209,6 +212,7 @@ struct adt7475_data { 
	u8 range[3];

	u8 pwmctl[3];

	u8 pwmchan[3];

	u8 enh_acoustics[2];



	u8 vid;

	u8 vrm;
@@ -700,6 +704,43 @@ static ssize_t set_pwm(struct device *dev, struct device_attribute *attr, 
	data->pwm[sattr->nr][sattr->index] = clamp_val(val, 0, 0xFF);

	i2c_smbus_write_byte_data(client, reg,

				  data->pwm[sattr->nr][sattr->index]);

	mutex_unlock(&data->lock);



	return count;

}



static ssize_t show_stall_disable(struct device *dev,

				  struct device_attribute *attr, char *buf)

{

	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	struct i2c_client *client = to_i2c_client(dev);

	struct adt7475_data *data = i2c_get_clientdata(client);

	u8 mask = BIT(5 + sattr->index);



	return sprintf(buf, "%d\n", !!(data->enh_acoustics[0] & mask));

}



static ssize_t set_stall_disable(struct device *dev,

				 struct device_attribute *attr, const char *buf,

				 size_t count)

{

	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);

	struct i2c_client *client = to_i2c_client(dev);

	struct adt7475_data *data = i2c_get_clientdata(client);

	long val;

	u8 mask = BIT(5 + sattr->index);



	if (kstrtol(buf, 10, &val))

		return -EINVAL;



	mutex_lock(&data->lock);



	data->enh_acoustics[0] &= ~mask;

	if (val)

		data->enh_acoustics[0] |= mask;



	i2c_smbus_write_byte_data(client, REG_ENHANCE_ACOUSTICS1,

				  data->enh_acoustics[0]);



	mutex_unlock(&data->lock);
@@ -1028,6 +1069,8 @@ static SENSOR_DEVICE_ATTR_2(pwm1_auto_point1_pwm, S_IRUGO | S_IWUSR, show_pwm, 
			    set_pwm, MIN, 0);

static SENSOR_DEVICE_ATTR_2(pwm1_auto_point2_pwm, S_IRUGO | S_IWUSR, show_pwm,

			    set_pwm, MAX, 0);

static SENSOR_DEVICE_ATTR_2(pwm1_stall_disable, S_IRUGO | S_IWUSR,

			    show_stall_disable, set_stall_disable, 0, 0);

static SENSOR_DEVICE_ATTR_2(pwm2, S_IRUGO | S_IWUSR, show_pwm, set_pwm, INPUT,

			    1);

static SENSOR_DEVICE_ATTR_2(pwm2_freq, S_IRUGO | S_IWUSR, show_pwmfreq,
@@ -1040,6 +1083,8 @@ static SENSOR_DEVICE_ATTR_2(pwm2_auto_point1_pwm, S_IRUGO | S_IWUSR, show_pwm, 
			    set_pwm, MIN, 1);

static SENSOR_DEVICE_ATTR_2(pwm2_auto_point2_pwm, S_IRUGO | S_IWUSR, show_pwm,

			    set_pwm, MAX, 1);

static SENSOR_DEVICE_ATTR_2(pwm2_stall_disable, S_IRUGO | S_IWUSR,

			    show_stall_disable, set_stall_disable, 0, 1);

static SENSOR_DEVICE_ATTR_2(pwm3, S_IRUGO | S_IWUSR, show_pwm, set_pwm, INPUT,

			    2);

static SENSOR_DEVICE_ATTR_2(pwm3_freq, S_IRUGO | S_IWUSR, show_pwmfreq,
@@ -1052,6 +1097,8 @@ static SENSOR_DEVICE_ATTR_2(pwm3_auto_point1_pwm, S_IRUGO | S_IWUSR, show_pwm, 
			    set_pwm, MIN, 2);

static SENSOR_DEVICE_ATTR_2(pwm3_auto_point2_pwm, S_IRUGO | S_IWUSR, show_pwm,

			    set_pwm, MAX, 2);

static SENSOR_DEVICE_ATTR_2(pwm3_stall_disable, S_IRUGO | S_IWUSR,

			    show_stall_disable, set_stall_disable, 0, 2);



/* Non-standard name, might need revisiting */

static DEVICE_ATTR_RW(pwm_use_point2_pwm_at_crit);
@@ -1112,12 +1159,14 @@ static struct attribute *adt7475_attrs[] = { 
	&sensor_dev_attr_pwm1_auto_channels_temp.dev_attr.attr,

	&sensor_dev_attr_pwm1_auto_point1_pwm.dev_attr.attr,

	&sensor_dev_attr_pwm1_auto_point2_pwm.dev_attr.attr,

	&sensor_dev_attr_pwm1_stall_disable.dev_attr.attr,

	&sensor_dev_attr_pwm3.dev_attr.attr,

	&sensor_dev_attr_pwm3_freq.dev_attr.attr,

	&sensor_dev_attr_pwm3_enable.dev_attr.attr,

	&sensor_dev_attr_pwm3_auto_channels_temp.dev_attr.attr,

	&sensor_dev_attr_pwm3_auto_point1_pwm.dev_attr.attr,

	&sensor_dev_attr_pwm3_auto_point2_pwm.dev_attr.attr,

	&sensor_dev_attr_pwm3_stall_disable.dev_attr.attr,

	&dev_attr_pwm_use_point2_pwm_at_crit.attr,

	NULL,

};
@@ -1136,6 +1185,7 @@ static struct attribute *pwm2_attrs[] = { 
	&sensor_dev_attr_pwm2_auto_channels_temp.dev_attr.attr,

	&sensor_dev_attr_pwm2_auto_point1_pwm.dev_attr.attr,

	&sensor_dev_attr_pwm2_auto_point2_pwm.dev_attr.attr,

	&sensor_dev_attr_pwm2_stall_disable.dev_attr.attr,

	NULL

};